ÉCOLE POLYTECHNIQUEFÉDÉRALE DE LAUSANNE

L M RLCPC / 9 février 2005

LABORATOIRE DEMÉCANIQUE DES ROCHES

Laboratory tests in rock mechanics

J.-F. Mathier

avril 2000 2

EPFL - LMR

LMR Equipments

g Laboratoryn 500 and 2000 kN Presses n triax cells Hoek, Legep, GDSn Direct shear tests

g 2 test hallsn TRIROC Press 3500 kNn Physical modelling

4 tunnel excavation, face stability4 rockfall4 Impact of falling blocs

avril 2000 3

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500 kN and 2000 kN Presses

avril 2000 4

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Standard tests

g Standard testsn Triaxn Unconfined compression, tractionn Modul E, Poisson coefficient n Indirect shear testn Swellingn Creep

g Database

EPFL - LMR

0

20

40

60

80

100

0 5 10 15 20

σ 1

σ3

[MPa

]

[MPa]

σ1= σ

3+( σ

3+ ) m* s* a

a = 0.61m* = 91.17s*= 8.66R = 0.99

0

20

40

60

80

100

0 5 10 15 20

σ 1

σ3

[MPa

]

[MPa]

σ1= σ

3+( σ

3+ ) m* s* a

a = 0.50m* = 441.70s*= 216.69R = 0.98

3. Strong tectonised

0

20

40

60

80

100

0 5 10 15 20

σ 1

σ3

[MPa

]

[MPa]

σ1= σ

3+( σ

3+ ) m* s* a

a = 0.70m* = 11.79s*= 1.32R = 0.99

0

20

40

60

80

100

0 5 10 15 20

σ 1

σ3

[MPa

]

[MPa]

σ1= σ

3+( σ

3+ ) m* s* a

a = 0.75m* = 6.14s*= 0.31R = 0.98

1. Poorly tectonised 2. Tectonised

4. Very strong tectonised

Triaxial tests : Behaviour of cataclastic rocks

3Several degrees of tectonisation

3Ex: Quartzitic sandstones

numerous tests

good correlation

Thesis Jean Habimana

avril 2000 6

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Direct shear tests on discontinuities

avril 2000 7

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Swelling

g 3 types of testingg Free swell, swell pressure, Huder-Ambergg Procedure AFNORg Interpretationg Mineralogyg Correlations ?

avril 2000 8

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Creep : experimental device

3 triaxial cells for creep tests

Pressure controls

avril 2000 9

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Geotechnical Database

g Data storagen EXCEL versionn Filemaker searchn ACCESS version in progress

g 6000 samplesn 4000 unconfined compressionn 3400 modul En 2200 brasilian testsn 900 triax

g Types of rocksn 10% igneous rocksn 65% sedimentary rocksn 25% metamorphic rocks

g Geographical distribution

avril 2000 10

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Geotechnical Database

French Switzerland

Structures

• highways

• tunnels

• dams

avril 2000 11

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Special tests

g Special testsn Permeabilityn Acoustic emissionn Fracture toughnessn Abrasivity

avril 2000 12

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Permeability

g Ex: SELFRAC Projectg div. and conv. Permeabilty

in hollow cylinderg Boom clay

n K = 10-12 m/sg Opalinus clay

n K = 10-13 m/s

LVDT

Strain gages

Inner drain

outer drain

jacket

Load cell

Pressure sensor

valve

inner pressure

controller

cell pressure

controller

Outer pressure

controller

personal computer pressures control

volumes and pressures acquisition

Personal computer additional

data acquisition

LVDT

Strain gages

Inner drain

outer drain

jacket

Load cell

Pressure sensor

valve

inner pressure

controller

cell pressure

controller

Outer pressure

controller

personal computer pressures control

volumes and pressures acquisition

Personal computer additional

data acquisition

LVDT

Strain gages

Inner drain

outer drain

jacket

Load cell

Pressure sensor

valve

inner pressure

controller

inner pressure

controller

cell pressure

controller

cell pressure

controller

Outer pressure

controller

Outer pressure

controller

personal computer pressures control

volumes and pressures acquisition

personal computer pressures control

volumes and pressures acquisition

Personal computer additional

data acquisition

avril 2000 13

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Acoustic emission –Kaiser effect

3Crack growth Li 1996

8 cm

16 cm

Preloading

Loading andAE measurement

avril 2000 14

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Fracture toughness

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14

déplacement vertical [mm]

forc

e [k

N]

5.1maxmin / DFAKCB =

[ ] DSDaDaA oo /)/(85.9/15.784.1 2min ++=1.012.020.026632080

1.09.015.020024060

1.08.313.818322055

taohSLD

a0

h

KCB = 1.02

avril 2000 15

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CERCHAR abrasivity test

70 N

1 cm2

1

21

avril 2000 16

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LCPC Abrasivity test (NF P 94-430-2)

0

0

GPPABR −

=

avril 2000 17

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Abrasivity scales

quartzitevery abrasive20004 - 6

graniteabrasive15002 - 4

gneissmedium abrasive10001 - 2

sandstonepoor abrasive5001

limestone, slatevery poor abrasive00 - 1

Example of rockEvaluationABRICA

avril 2000 18

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Comparison between ICA-ABR

0

300

600

900

1200

1500

1800

0 1 2 3 4 5 6

ICA

LC

PC [g

/ton]

Granodiorit Biotit-Serizit Gneis Granitigneous rocks metamorphic rocks sandstoneOlivine basalt Porphyritic basalt Tholeitic basalt

Ratio ABR / ICA ~ 300

Rocks from Switzerland + Island

avril 2000 19

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Accreditation

g LMS+LMRg ISO 17005g Type Cg Renewed till 2009g Normalisationg Cross tests

avril 2000 20

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Cross tests

g 8 laboratoriesg 4 types of rocks

n Carrare marblen Molassic sandstonen Anhydrit from Bexn Limestone from Sixt (France)

g 4 different tests n Densityn Unconfined compression strengthn Modul En Brasilian test

avril 2000 21

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Unconfined compression

189.9204.3198.3200.9184.8186.4165.7193.1188.5Limestone

104.3101.5105.8104.6100.7107.5106.7103.4104.7Carrare marble

158.1144.0153.0167.5162.9158.8163.2158.6154.8Anhydrit

10.38.912.211.59.19.98.59.812.1Molassicsandstone

MeanL1- L9

L9L8bL8aL7L5L3L2L1

avril 2000 22

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TRIROC Press Thesis F. Pellet

avril 2000 23

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Behaviour of bolted rock mass – F. Pellet

Joint oriented to 45 et 60°

1 à 5 joints

2 types of material(plaster and limestone)

Bolts ø 3mm

avril 2000 24

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Base friction apparatus

avril 2000 25

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Base friction apparatus: example of application

g Excavation of shallow tunnel (Thesis M. Karaca 1991)

avril 2000 26

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Base friction apparatus: example of application

g qualitative simulation of toppling

avril 2000 27

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Shallow tunnel modelling (scale 1:20)